\documentclass{standalone}
\usepackage{tikz}
\usepackage{ctex,siunitx}
\setCJKmainfont{Noto Serif CJK SC}
\usepackage{tkz-euclide}
\usepackage{amsmath}
\usepackage{wasysym}
\usepackage{circuitikz}
\usetikzlibrary{patterns, calc}
\usetikzlibrary {decorations.pathmorphing, decorations.pathreplacing, decorations.shapes,}
\ctikzset{bipoles/length=1cm}
\begin{document}
\small
\begin{circuitikz}[>=latex, scale=1.0,european]
  % \useasboundingbox(0.9,0)rectangle(5.1,5);
  \foreach \x in {-0.95,1.05}
  {
    \fill[top color=gray,bottom color=gray,middle color=white] (\x,0)ellipse(0.3 and 1.0);
    \fill[top color=gray,bottom color=gray,middle color=white] (\x,1)rectangle++(-0.1,-2);
    \fill[lightgray,even odd rule] (\x-0.1,0)ellipse(0.3 and 1.0)(\x-0.1,0)ellipse(0.03 and 0.1);
  }
  \node at (-1,-0.3){$+Q$};
  \node at (1,-0.3){$-Q$};
  \draw[rounded corners=2mm](-2.2,-1.7)rectangle(2.2,1.6);
  \draw[thin,|<->|](-1,-1.3)--(1,-1.3)node[midway,above]{$d$};
  \draw(-1,-1)--(-3,-1)--(-3,-2.5) to [battery] (3,-2.5)--(3,-1)--(1,-1);
\end{circuitikz}
\end{document}